To help you decide which solar system size is right for your Perth home, we’ve created the easy to read size comparison chart below. Simply select the average amount your current electricity bill comes to, and follow the row across to find out what size model would best suit your energy needs.
| I have an average electricity bill of… | Solar system size | Avg cost of solar system in Perth | No. of panels | Power generated | How much can I save? | Average payback period |
| $120 per cycle | 1.5kW | $2,490 – $3,200 | 5 | 7 units/day | $105 per electricity bill, when operating at full capacity | Within 5 years |
| $150 per cycle | 2kW | $2,690 – $4,100 | 6 | 9 units/day | $90 – $145 per electricity bill | Within 4 years |
| $220 or more per cycle | 3kW | $2,990 – $5,600 | 10 | 13 units/day | $120 – $200 per electricity bill | 3 years |
| $300 or more per cycle | 4kW | $3,660 – $6,900 | 13 | 18 units/day | $140 – $270 per electricity bill | 3-4 years |
| $350 or more per cycle | 5kW | $3,990 – $8,000 | 17 | 22 units/day | $180 – $350 per electricity bill | 2.5-4 years |
| $450 or more per cycle | 6kW | $3,990 – $9000 | 20 | 26 units/day | $200 – $400 per electricity bill | 2.5-4 years |
| $500 plus per cycle | 7kW | $7,170 – $10,900 | 23 | 31 units/day | $300 – $450 per electricity bill | 2.5-4 years |
| $600 plus per cycle | 8kW | $7,500 – $11,200 | 27 | 35 units/day | $300 – $505 per electricity bill | 2.5-3.5 years |
| $700 plus per cycle | 9kW | $9,600 – $13,600 | 30 | 40 units/day | $300 – $600 per electricity bill | 3-5 years |
| $800 or more per cycle | 10kW | $9,490 – $14,300 | 33 | 44 units/day | $400 – $700 per electricity bill | 3-5 years |
Please note this chart has been designed as a rough guide only. A number of additional factors need to be considered including the size of your roof, what time of the day you use the majority of your energy, and your future circumstances.
Your existing roof is the biggest indication of your solar system size, and where your panels will be positioned. For example, if you only have free roof space facing east, this is where your panels will need to go. In order to maximise your savings, you’ll have to plan your energy usage accordingly, (for example, turning the dishwasher and washing machine on in the morning).
As the sun in Perth rises in the east and sets in the west, the sun is at its strongest when it sits north in the sky at midday. Therefore, solar power systems can be installed on roofs facing anywhere from due east to due west, although we recommend north for best absolute production. This is a general rule however, as a well-designed system will match your home’s electricity consumption pattern.
If the morning is your busiest time of the day (think getting the kids ready for school, doing the washing and ironing, plus turning on the dishwasher) it’s best to install panels on the eastern roof.
If the afternoon is your peak energy usage time (everyone is home from work and school, the TV is on, as well as the computer and the air conditioner), you’ll want to install your solar power system on your western roof.
If you use the most energy from mid-morning to the afternoon (stay at home parents, retirees, or those working from home) installing panels on the northern roof will give you the best return on your investment.
If your energy usage is spread evenly throughout the day, purchasing a solar system size of between 4-5kW will give you the ability to spread your panels across your roof.
If you’ve looked at installing a new pool, starting to work from home, or welcoming a new member of the family, you should carefully consider the size of your solar system with your future circumstances in mind. It’s much easier and more cost effective to install a larger size solar system, then it is to expand in the long run.
Having installed more than 16,000 systems across the Perth metropolitan region, Infinite Energy has the experience to help you decide the best system size for your energy needs.
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